It is known in the art of building structure heating to propel air, as by means of a fan, from a lower level to an upper level. Often systems of this nature are deficient in that they require either continuous fan operation, which itself utilizes excess amounts of energy, or constant manual intervention, which is both inefficient and time consuming.
The invention disclosed in my U.S. Pat. No. 4,915,294, issued Apr. 10, 1990, relates to a system which operates automatically to lessen the differential of temperatures in upper and lower building level interiors. The system operates by redistributing the hot air which normally rises to the upper levels of a multi-story building to a lower level, thereby providing a more uniform temperature throughout the building.
My U.S. Pat. No. 4,993,629, issued Feb. 19, 1991, is, in essence, an improvement of the system disclosed in my U.S. Pat. No. 4,915,294. In common therewith, the invention of U.S. Pat. No. 4,993,629 incorporates structure which is operable to automatically initiate an air flow from an upper level interior to a lower level interior when temperatures sensed by sensors in the interiors differ to a predetermined extent. The arrangement of the latter patent, however, differs from the earlier invention in that it incorporates heat generating means and controls the operation of the heat generating means to heat the air delivered to the lower level interior after the temperature differential between the upper level and the lower level interiors has reached a predetermined level below the temperature differential required to initiate air flow between the upper and lower interiors. In other words, with the system of U.S. Pat. No. 4,993,629, the burner of a furnace or other heat generating means is not actuated until efficient use is made of the heated air in an upper level interior to heat the lower level interior.